Radio Telescopes Reveal Youngest Stellar Corpse

Astronomers using a global combination of radio telescopes
to study a stellar explosion some 30 million light-years
from Earth have likely discovered either the youngest black
hole or the youngest neutron star known in the Universe.
Their discovery also marks the first time that a black hole
or neutron star has been found associated with a supernova
that has been seen to explode since the invention of the
telescope nearly 400 years ago.

An artist's impression of Supernova 1986J.
The newly discovered nebula around the black hole
or neutron star in the center is shown in blue,
and is in the center of the expanding, fragmented
shell of material thrown off in the supernova
explosion, which is shown in red.
CREDIT: Norbert Bartel and Michael F. Bietenholz,
York University; Artist: G. Arguner(Click on image for larger version)

Multi-Frequency Closeup View (201K)
Blue and white area shows the nebula surrounding the
black hole or neutron star lurking in the center of the
supernova. This nebula is apparent at a higher radio
frequency (15 GHz). The red and also the contours show the
distorted, expanding shell of material thrown off in the
supernova explosion. This shell is seen at a lower radio
frequency (5 GHz).
CREDIT: Michael F. Bietenholz and Norbert Bartel,
York University, Michael Rupen, NRAO, NRAO/AUI/NSF

A
supernova is the explosion of a massive star after it exhausts
its supply of nuclear fuel and collapses violently, rebounding
in a cataclysmic blast that spews most of its material into
interstellar space. What remains is either a
neutron star,
with its material compressed to the density of an atomic
nucleus, or a
black hole, with its matter compressed so
tightly that its gravitational pull is so strong
that not even light can escape it.

"SN 1986J has shown a brightly-emitting object at its center
that only became visible recently. This is the first time such
a thing has been seen in any supernova," said Michael Bietenholz,
of
York University in Toronto, Ontario. Bietenholz worked with
Norbert Bartel, also of York University, and Michael Rupen
of the
National Radio Astronomy Observatory (NRAO) in Socorro,
New Mexico, on the project. The scientists reported their
findings in the June 10 edition of Science Express.

"A supernova is likely the most energetic single event in the
Universe after the
Big Bang. It is just fascinating to see how
the smoke from the explosion is blown away and how now after all these
years the fiery center is unveiled. It is a textbook story,
now witnessed for the first time," Bartel said.

Analysis of the bright central object shows that its characteristics
are different from the outer shell of explosion debris in the
supernova.

"We can't yet tell if this bright object at the center is caused
by material being sucked into a black hole or if it results from
the action of a young
pulsar, or neutron star," said Rupen.

"It's very exciting because it's either the youngest black hole
or the youngest neutron star anybody has ever seen," Rupen said.
The youngest pulsar found to date is 822 years old.

Finding the young object is only the beginning of the scientific
excitement, the astronomers say.

"We'll be watching it over the coming years. First, we hope to find
out whether it's a black hole or a neutron star. Next, whichever
it is, it's going to give us a whole new view of how these things
start and develop over time," Rupen said.

For example, Rupen explained, if the object is a young pulsar,
learning the rate at which it is spinning and the strength
of its magnetic field would be extremely important for understanding
the physics of pulsars.

The scientists point out that it will be important to observe
SN 1986J at many
wavelengths, not just radio, but also in visible
light, infrared and others.

In addition, the astronomers also now want to look for simiilar
objects elsewhere in the Universe.